In a conventional electric fan apparatus, a wind direction shifting plate has been used as means for shifting the direction of a wind generated by a fan rotated by a motor, without shifting the air sending direction by the fan. When a motor has been used for rotating such wind direction shifting plate, the rotation of the fan motor rotary shaft or the rotation of the rotary shaft of a motor to rotate the wind direction shifting plate has been transmitted to the rotary shaft of the wind direction shifting plate through a reduction gear mechanism, thereby to rotate the wind direction shifting plate at a low speed. In such arrangement, however, if the wind direction shifting plate is stopped rotating by external force, there is a possibility of the motor being burnt out. In addition, if the wind direction shifting plate is forcibly rotated from their stop position, there is a possibility of the reduction gear mechanism being damaged.
When the pressure of a wind generated by the fan has been utilized as means for rotating the wind direction shifting plate, there has been used a braking mechanism for controlling the rotating speed of the wind direction shifting plate so as to permit the wind direction shifting plate to be rotated at a low speed. In such arrangement, even if the wind direction shifting plate is forcibly stopped rotating by external force, it provokes no problems, but if such plate is forcibly rotated, there is a possibility of the braking mechanism being damaged.
In order to prevent damages to the motors, the reduction gear mechanism and the braking mechanism, there has been proposed an electric fan apparatus in which the rotary shaft of the braking mechanism or the speed reduction mechanism has been coupled to the wind direction shifting plate through clutch means. However, when such clutch means has been constituted by ball clutch means using springs and balls, such arrangement has presented defects that the number of parts to be used has been increased and the assembling work has been very difficult.
On the other hand, when the wind direction shifting plate has been rotated by the wind pressure and if symmetric portions of the wind direction shifting plate with respect to its rotating center have been unbalanced in weight, the rotating speed of the wind direction shifting plate has become uneven and therefore has not been smoothly rotated since the wind pressure exerted to the wind direction shifting plate has been constant at all times.